1. Technical Field
The present invention relates to a touch detection device.
2. Description of the Related Art
As described in, for example, Japanese Patent Application Laid-open Publication No. 2012-073783, a mutual capacitance method is known as a method employed in a touchscreen panel. In this method, a drive signal is applied to one (drive electrode) of two electrodes provided so as to be opposed to each other, and a touch operation is detected based on a change in electrostatic capacitance generated between the two electrodes.
In the mutual capacitance method, a detection circuit is provided that detects an electrical signal output from the other (detection electrode) of the two electrodes to determine whether the touch operation is made. In the mutual capacitance method, accuracy of detection per unit area corresponds to the number of intersections between sets of the two electrodes intersecting in a plan view. Therefore, to achieve at least either one of improvement in fineness in detection pitch or increase in size of a detection surface without decrease in fineness in detection pitch, the number of intersections between the sets of the two electrodes in the touchscreen panel needs to be increased. Simply increasing the number of the detection electrodes for increasing the number of intersections between the sets of the two electrodes necessitates an increase in number of input channels of the detection circuit corresponding to the number of the detection electrodes. The increase in number of input channels of the detection circuit brings about a problem of, for example, increases in size and cost of the detection circuit.
For the foregoing reasons, there is a need for a touch detection device capable of detecting the touch operation with a smaller number of the input channels of the detection circuit than the number of the detection electrodes.